In connection with the planning and execution of a project involving a discrete number of tasks, some of which bear a required sequential relationship to one another and others of which are sequentially and temporally independent of one another, it is useful to prepare a project evaluation and review technique (PERT) chart graphically illustrating each of the tasks as a separate block with lines interconnecting the blocks to illustrate their relative sequence. These charts may be prepared manually for projects involving a relatively small number of tasks, but the effort required to generate such a chart increases exponentially with the number of tasks. Accordingly, computer programs have been developed which will generate the charts automatically given operator input as to the identity of the tasks, their duration, and their sequence relative to one another. Some of these programs will additionally generate related charts and alphanumeric listings useful in accomplishing the tasks such as a work breakdown structure or Gantt chart. Systems employing such programs are illustrated in U.S. Pat. Nos. 3,380,177, 3,735,109 and 5,101,340.
While these programs as a class, have enjoyed substantial commercial success, and are usually employed when planning a project of any substantial magnitude, they place a heavy burden on the user in generating the input information and in particular the sequential order of the tasks relative to one another.